This invention relates to catalysts or catalyst precursors for forming 1-butenes from a 1-olefin reactant.
Prior to the present invention, there have been no known homogeneous catalysts for converting a terminal olefin selectively to a 1-butene or 2,3-disubstituted 1-butene at room temperature or above. Known homogeneous dimerization catalysts readily isomerize the initially formed 1-butene to the thermodynamically more stable internal butene. It is also known that heterogeneous catalysts such as chromocene on alumina or silica produce 1-butene from ethylene. In addition, other selected dimerization reactions are known. However, these reactions generally are successful for only one olefin, e.g., the use of KC.sub.8 to dimerize propylene selectively to 4-methyl-1-pentene.
Accordingly, it would be desirable to provide a homogeneous catalyst system for selectively forming 1-butenes which can be used with any one of a plurality of 1-olefin feed compositions.